Bituminous ash remover for underfeed stokers



Jul 5, 1938.

H. c. CARTER anummous ASH REMOVER FOR UNDERFEED STOKERS Filed June 18, 1935 2 Sheets-Sheet 1 H.C. CARTER E fl TTU NEV Patented July 5, 1938 UNITED STATES PATENT OFFICE BITUMINOUS ASH REMOVER FOR UNDER- FEED STOKERS land, Oreg.

Application June 18,

7 Claims.

This invention relates generally to underfeed stokers, and particularly to bituminous ash removers therefor.

The main object of this invention is the construction of an ash remover for bituminous underfeed stokers which will so affect the manner in which the coal is consumed that it will reduce the tendency to form clinkers, thereby simplifying the problem of removing the incombustibles from the combustion zone.

The second object is to provide an improved form of ash remover which incorporates a means for delivering air to a larger area of the bumingsurface than is ordinarily possible and at the same time make it possible to vary the rate of flow of said air to various portions of the fuel bed.

The third object is to construct an ash remover which makes possible the use of small discharge openings for the ashes at the same time eliminating shearing points between the ash ports and the ash removal arms with the consequent reduction of noise which accompanies clinkers crushing and also avoiding the difficulty of having clinkers wedged between the ash removal arms and the ash plate.

I The fourth object is to so construct the ash remover that the coal will be burned over a relatively large area at a temperature below the fusing point of the incombustibles bringing about a condition which is extremely favorable tothe mechanical removal of the ashes.

The fifth object is to construct a retort and tuyere assembly together with the surrounding ash rings with a relatively small inside tuyre diameter where the green coal enters the fuel bed for the purpose of breaking up any coke columns which might form and also to increase the active burning area for the coal.

The sixth object is to provide a special form of ash ring adapted to be selectively rotated to various positions 'for the purpose of varying the ratio of the air flow to the inner part of the retort with relation to the flow to an outer portion of the retort and also to obtaina regulation'for the pressure of the air flowing toward the outer portion 'of' the retort.

The seventh object is to construct the portion of the tuyre which is subjected to the most intense heat, aswell as the projecting arms, in the form of an integral casting of a high alloy heat resisting steel and to so mount same that it -may be easily replaced if necessary.

I accomplish these and other objects in the manner set forth in the following specification as 1935, Serial No. 27,195

illustrated in the accompanying drawings, in which:

Fig. 1 is a side elevation of a complete stoker showing the ash removal worm exposed and the fuel feed duct broken away in section to disclose the fuel feed worm and showing the outline of the furnace in dotted lines.

Fig. 2 is a vertical section taken along the line 2-2 in Fig. l.

Fig. 3 isa fragmentary vertical developed sec- 10 justed position.

Fig. 6 is a section taken along the line 6- 6 in Fig. 5.

Fig. 7 is a section taken along theline 1-1 in Fig. 2.

Similar numbers of reference refer to similar parts throughout the several views.

Referring in detail to the drawings, there is shown a hopper Hi from which coal is conveyed through a coal tube ll by means of a coal feeding worm l2 which is driven from a motor l3 through gearing contained within a transmission casing Id. The coal tube ll terminates in a retort l5 which is surrounded by the plenum chamher walls IS. A floor plate 11 forms the bottom of the plenum chamber l8, while the side walls l6 merge into the horizontal top I9 which extends into the retort l5.

A circular plate 20 is mounted on the top It and secured thereto by means of bolts 2!. Openings 22 are formed through the top l9 and the plate 20 for the upward passage of air from the plenum chamber Hi to which air is supplied through an air duct 23 by a fan (not shown). Rotatably mounted on the plate 20 is the outer tuyere wall 24, whose horizontal flange 25 rotates upon the plate 20 and extends beyond thesouter edge of the plate 20. A toothed ring 26 is secured to the underside of the extending portion of the flange 25 and meshes with the inclined ash removing worm 21 which occupies the ash removing duct 28 and is driven from its upper end through a universal joint (not shown) by means of a sprocket wheel 29 which is connected by the chain 30 to the power takeoff sprocket wheel 3| on the side of the transmission casing H. The upper side of the end 32 of the ash removing duct 28 is cut away to expose theworm 21 to the toothed ring 26 and to the ashes which fall downwardly around the .outside of the plenum chamber l8.

Projecting inwardly from the outer tuyere wall 24 are the spokes 33 which connect with the circular inner tuyre wall 34, whose lower end 35 extends downwardly into the opening 36 formed in the center of the plate 20. The interior of the wall 34 registers with the interior of the retort l5. The end 35 preferably does not engage the wall of the opening 36 or the top l9. The top side 31 of the tuyre wall 34 slopes downwardly from its outer and inner edges to an intermediate line 38.

Supported on the top side 31 and on the top of the outer tuyre wall 24 is the element 39, from the top face of which projects a plurality of radial arms 40, the underside of each of which has formed therein a channel 4| through which air can pass upwardly from the space 42 through the opening 43 and be discharged downwardly from the arms 40. Within the wall 34 are formed the air outlets 45, the top side of which is formed by the element 39. The outer portion 46 of the element 39 rests upon the wall 24 in whose upper edge are formed the notches 41 through which air can pass from the space 42 to the outer side of the wall 24 without passing through the arms 49.

The element 39 is held in position by means of the hooks 48 which engage the lugs 49 formed on the inner side of the wall 24 when the elements 24 and 39 are rotated with relation to each other in one direction and are prevented from becoming disengaged byrotation in an opposite direction by means of a headed pin 58 which extends downwardly through the element 39 on the opposite side of the next adjacent lug 49.

Secured to the outer side of the walls l6 are the upwardly extending brackets 5| whose upper ends 52 occupy the recesses 53- in the outer rim 54 from which extend inwardly the radial arms 55, whose upper edges 56 are spaced below the under edges 51 of the arms 40. -Resting upon the upper edges 56 of the arms 55 is an annular outer ash ring 58, whose outermost edge 59 is spaced from the innermost surface 68 of the outer rim 54. The edges 59 and 6| of the outer ash ring 58 are preferably undercut, as shown.

On the underside of the outer ash ring 58 are formed the notches 62 which engage the arms 55 and serve to prevent the rotation of the ring 58 as well as to hold same concentric with relation to the outer portion 46 of the element 39. Between the inner edge 6| of the ash ring 58 and theouter pqrtion 46 of the element 39 and also resting upon the arms 55 is an inner adjustable ash ring 63, whose innermost edge 64 is parallel with the outer surface of the portion 46 and'is vertically slidable with relation thereto.

The underside of the ring 63 is provided with a series of notches 65, 66, 61, 68 and 69 of increasing depth making it possible to secure various adjustments for the elevation of the inner ring 63, whose outermost edge is undercut. The ring- 63 may be adjusted vertically by rotating same circumferentially until one of the desired notches 65 to 69 engages its respective arm 55. It will be noted that the inner edge 64 of the ring 63 extends downwardly sufficiently far when the ring 63 is in its lowermost position to coverthe ports formed by the notches 41 and the tuyre wall 24.

It is desirable to surround the rim 54 with a refractory material II which extends downwardly to the floor line forming an ash well 12 into which the ash duct end 32 extends.

The operation of the device is as follows:

Assume that the stoker is being operated and that coal is being fed through the fuel feed duct H by the worm l2 into the retort I5 from whence it passes upwardly within the walls 34 of the tuyere element. As the fuel passes the outlets 45 and receives air therefrom in the presence of the heat being generated about same, combustion begins fairly close to the center of the retort and as the burning coals are moved outwardly by the upwardly fed stream of green coal, the partially burned coal passes over the element 39 across the intervening space 13 between the elements 39 and 63 which is negligibleand across the space 14, which is variable depending upon the position in which the element 63 is placed upon the arms 55, after which the almost completely burned fuel moves out wardly to the space between the outer ash ring 58 and the rim 54.

It will be borne in mind that while this is taking place, the element 39 with its supporting wall 34 and radiating arms 40 are all rotating due to the action of the worm 21 upon the wheel 26, and that during this rotation, air is passing to the arms 40 cooling and protecting same and at the same time affording additional combustion air to material resting on the ash rings 58 and 63. Obviously, the proportion of air being delivered through the outlets 45 in relation to the amount and pressure of air delivered through the spaces 14 and 15 will vary according to the position of the inner adjustable ash ring 63.

In other words, air is supplied to the burning fuel close to the center of the combustion zone and is delivered in annular rings of increasing diameter toward the outer edge of the combustion zone, and the amount and pressure of the air thus delivered may be easily adjusted to suit the operating conditions.

It will also be noted that by providing this large burning area, it is less necessary to force the fire and it is therefore possible to avoid tem-' or by an agitation set up through the movement of the arms themselves.

I claim:

1. An underfeed stoker having in combination a revolvable tuyre section comprising spaced circular inner and outer walls, a retort including means for discharging fuel upwardly through the retort into the tuyere section, means for admitting air to the space between the tuyre walls, the outer tuyere wall having air discharge openings therein, said revolvable tuyre section having radial arms projecting horizontally from the top edgethereof, each of said arms having an air passage communicating with the interior of the tuyre section and having a discharge opening on the under side thereof, a stationary ash ring concentrically spaced from said tuyere section, a vertically adjustable ash ring disposed within the space between the tuyere section and the stationary ash ring, said vertically adjustable ash ring constituting a means for controlling the flow of air through the outermost tuyere openings and through the annular space between said ash rings.

2. An underfeed stoker having in combination a revolvabletuyere section having a toothed ring attached thereto, an ash removing worm meshing with said toothed ring, means for driving said worm, the upper portion of said tuyere section having a cylindrical exterior provided with air outlets, a vertically adjustable ash ring disposed around said cylindrical tuyre portion adapted in control the flow of air through said outlets, r. stationary ash ring disposed outside of said vertically adjustable ash ring, the adjacent edges of said ash rings being beveled in a manner to vary the clearance between same when said adjustable ring is moved vertically and a retort disposed under said tuyere section having means for discharging coal upwardly therethrough.

3. An underfeed stoker having in combination a revolvable tuyre section comprising concentric spaced inner and outer walls, said tuyere section having a toothed ring attached thereto, an ash removing worm meshing with said toothed ring, means for driving said worm, the upper portion of said tuyre portion having a cylindrical exterior provided with air outlets, a vertically adjustable ash ring disposed around said cylindrical tuyere portion adapted to control the flow of air through said outlets, a stationary ash ring disposed outside of said vertically adjustable ash ring, the adjacent edges of said ash rings being beveled in a manner to vary the clearance between said ash rings when said adjustable ring is moved vertically and a retort discharging upwardly into said tuyre section.

4. An underfeed stoker having in combination a revolvable tuyere section comprising spaced circular inner and outer walls, said tuyere section having a toothed ring attached thereto, an ash removing ring meshing with said toothed ring, means for driving said worm, the upper portion of said tuyere section having a cylindrical exterior provided with air outlets, a vertically adjustable ash ring disposed around said cylindrical tuyere portion adapted to control the flow of air through said outlets, a stationary ash ring disposed outside of said vertical adjustable ash ring, the adjacent edges of said ash rings being beveled and a plurality of radial arms projecting outwardly from the inner upper edge oi. said tuyere section and provided with channels communicating with the interior of the tuyere section and discharging downwardly upon said ash rings.

5. A stoker having a retort and means for feeding fuel upwardly therethrough, a revolvable circular tuyere section comprising concentrically spaced inner and outer walls disposed immediately above the level of the discharge opening of said retort, the outer side of said tuyere section being cylindrical and perforated, an annular adjustable ash ring disposed around the cylindrical portion of said tuyre section constituting a means for varying the flow of air through its perforations, a stationary ash ring disposed around the adjustable ash ring and spaced therefrom, a rim supporting said stationary ash ring and projecting upwardly therefrom, a toothed ring attached to said tuyere section and an inclined ash removing worm meshing with said toothed ring.

6. A stoker having in combination a tuyere section comprising spaced circular inner and outer walls, the inner walls constituting the upper portion of aretort andthe space between the inner and outer walls constituting an air supply chamher, said outer wall having air outlets therein, an adjustable ash ring disposed around said outer wall adapted to be adjusted vertically for the purpose of controlling the flow of air through said outlets and means for rotating said inner and outer walls.

7. An underfeed stoker having in combination a circular revolvable tuyere section having spaced inner and outer walls, said tuyre section having an open underside for the admission of air to the space between said walls, said tuyere section having air discharge openings in its inner and outer walls, said tuyere section having radial arms projecting horizontally outward from the top edge thereof, each of said arms having an air passage communicating with the interior of the tuyere section and having a discharge opening on the underside thereof, a retort discharging upwardly into said tuyere section, means for feeding fuel upwardly through the retort, a stationary ash ring concentrically spaced from said tuyere section and a vertically adjustable ash ring disposed within the space between said tuyere section and' stationary ash ring, said vertically adjustable ash ring constituting a' means for controlling the flow or air through, the outermost tuyere openings and through the annular space between said ash rings.

HASKELL C. CARTER. 

